[Cerebral hemodynamics in occlusive diseases of major extracranial arteries].

The blood flow was studied in occlusive disorders of major extracranial blood arteries. Doppler ultrasound was used to quantify the blood flow and velocity in 120 patients. Four stenosis degrees were singled out. In the 1st one, internal carotid artery (ICA) was narrowed by 50%, and blood flow and velocity were reduced by more than 35% as related to normal levels. In 2nd degree stenosis. ICA blood flow decreased below the 65% level and ante- and retrograde blood flow was detected in orbital artery. In 3rd grade stenosis (over 75% ICA occlusion) the retrograde flow in the orbital arteries was recorded and ICA blood flow was considerably reduced. ICA occlusion featured no blood flow in ICA and orbitals, or high retrograde orbital blood flow (p less than 0.001). Reliable criteria were developed for detection of vertebral and ICA stenosis.